Apparatus for preparing and feeding fine fuel.



R. PITCAIRN.

APPARATUS FOR PRBPARING AND FEEDING FINE FUEL.

APPLICATION FILED FEB. 19, 1912.

Patented Dec. 31, 1912.

""m'll" "."hulllunlllll UNITED STATES PATENT OFFICE.

ROBER'I` PITCAIRN, O F DENVER, COLORADO, ASSIGNOR OF ONE-HALF TO THE STEARNS- ROGER MANUFACTURING COMPANY, COLORADO.

OFYDENVERrCOLORADO, A CORPORATION OF APPARATUS FOR PREPARING AND FEEDING FINE FUEL.

Specification of Letters Patent. 'Application med February 19, 1912. seal No. 678,542.

' Patented Dec. 31, 1912.

land Feeding Fine Fuel; and I do hereby declare the following to be a full, clear` and exact description of-tlie invention, such as will enable others skilled inv the art'to which it appertainsto make and use the same. y

This invention relates to an apparatus for preparing and feeding fine fuel, such as coal, with appropriate quantities of air to a furnace or other combustion apparatusA wherein the admixture of pulverized lfuel and air is burned in suspension.

The object of theinvention is to provide la simple, durable, compact and efficient apparatus to simultaneously pulverize the fuel and intimately admiX the same with the requisite quantities of air and .eject the same through the medium of the admixed air intoA the combustion chamber so that combustion is effected under lthe most advantageous and economical conditions. C' y .To this end, the invention comprises a casing provided with a longitudinal series of crushing chambers, preferably made up 0fl individual unitsheach of said chambers havingan inclined bottom with a restricted forced, a revoluble shaft in the casing associated with suitable means for driving said shaft, combined air-propelling and fuel crushing blades on said shaft, operating'in the lrespective crushing chambers, together vwith inlet and outlet orifices for fuel andV air in regulable quantities, the' whole being associated in a self-contained structure preferably located in vertical position in front l of the furnace or other combustion apparat-us and adapted to take coal from a hopper Vor other receptacle, comminute the same to the desired degree of fineness, mix` the comminuted fuel intimately with air in the proper proportions, and eject the adrnixture of line fuel and air into the combustion' space of the heating apparatus. By this apparatus, it is possible to avoid the necessity of storing fine fuel inbulk under conditionshighly 1conducive to disastrous explosions, and to enable the fuel to be pulve'rized' and mixed with the requisite quany orifice through which thefuel and air tities of air immediately at the'time and place whereit is required.

A preferred form of t-he invention is illustrated in the accompanying drawings, in which, 1

Figure 1 is a vertical longitudinal section through the apparatus. Fig. 2 is a horizontal section through one of the crushing chambers. Fig. 3 is a plan View of one of elements. 4Fig. 4 is an elevation of the crushing elements showing one of the blades in section. Y

Referring Vto the drawings,`1I indicates the casing or housing of the apparatus which comprises an upper member 2, divided by a cross partition 3 into tw'o sections or compartments, the top -section inclosing the connections between the driving motor and the shaft and also the gearing for operating ther cut-off or gate in the coal chute. The coal chute or inlet is preferably formed as a separate casting 5, attached to the upper memberl 2 of the casing and is provided with a sliding gate or'cut-oi:l 6 which is operated. by mechanism, to be hereinafter described, to supply the coal. or other fuel to be coniminuted in vappropriate quantities and at desired intervals to the apparatus. Below the chute 5, the member 2 is constricted to incoming coal toward the longitudinal axis of the apparatus. Below theV constricted throat 7, the member 2 of the casing is provided with a series of lateral air inlets cooperating with which isa movable ring-like opening'sS to any-desired extentand thereby to regulate the amount of air supplied to the apparatus. The casing or housing 1 further includes a seriesl of crushing chambers arranged in longitudinal alinement,

like element 9 provided with telescoping joints to connect the several rin .and the -adjacent casing sections as a su4 stantially air-tight conduit. Each of said ring-like sections 9 is provided with a downwardly inclined bottom 10 which is provided with a central orifice forming a constricted throat 11 through which the material passes and with serrations, ribs/(M thecombined air propelling and crushing.

a circular outlet 7 which serves to direct theN each of which chambers comprises a ringwhich serve, in conjunction with the rotary gate 8 which serves to open and close the the inner/ walls of each ring 9 are provided Y projections 12,` v

` eral element-s of the casing or housing 1 are -an adjustable thrust bearing 26, of any ap- I to the 'top of the casing or housing 1. In

' stood that said motor may be aturbine or aov . a suitable key or spline and the several ele 30 comprise combined air propelling and -ed upon a shaft 42 journaled in the casing.

crushing elements hereinafter described, to break up the coal and ultimately rducethe same to a desired'degree of fineness. The final element of the casing or housing con? sists of thecap or closure piece 14 provided with an outlet 15, which is connected by a` conduit 16 with the fire box of the furnace or other combustion apparatus. Thel sev* arranged in longitudinal series as shown,

of tie bolts 20 which pass through suitable lugs on the members 2 and 14 of the casing.

Mounted in bearing 22, carried by the cross partition 3 in the member 2 of the casing, and in a suitable step bearing 21 carried by the member 14 of the casing is a revoluble shaft 23, preferably supported by propriate form. The upper end of theshaftis preferably provided with a coupling 24 by means of which the shaft is connected with the stub shaft of a motor 25 secured the preferred form of the apparatus, 25 is an electric motor, although it will be underother suitable prime mover, or, in the alternative, it may be replaced by an appropriate form ofgearing or other form of transmissionl for imparting rotary movement to the Shaft 23.

Mounted ,upon the shaft 23` are a series of ropeller-like elements 30, one. occupying eac crushing chamber 9. These elements fuel crushing blades whichare set at an angle to the axis of rotation substantially like the blades of a marine propeller. Each of these airpropellingl and fuel crushing elements is secured to the shaft by means of ments are properly spaced so that they occupy the central space within the respectivey crushing chambers, by means of blocks 31,41 mounted on the shaft between the several chambers-30, and between the final elements 30 and the bearing block 27 surrounding the shaft and supported by the bottom of casing member 14. Preferably the forward face of each of the blades of the rotary crushing4 member is provided with a series of knobs or projections Awhich serve to break up the coal, in conjunction with the ribs or serrations on the interior walls of the crushing chambers 9.

Secured to the shaft 23, within the upper chamber 4 'of the housing is" a worm 40 which meshes with a worm wheel 41, mount-` To the outer end of the shaft 42, there is secured a crank 43, which is connect-ed by a pitman 44, with the sliding gate or cut-od 6 in the inlet chute 5, whereby7 the said cutthe communication betweenthe apparatus j and the fuel supply to regulate the amount of fuel furnished. A i j j V f The operation of the apparatus as described 'is substantially as follows: When power is applied to the shaft 23 by means of the motor 25 or other appropriate actuating mechanism, the combined air propelling and4 crushing elements 30 are rotated with the shaft and the gate or cut-off 6 is operated to admit. given quantities of fuel vfrom the storage bins by way of inlet chute 5 td the interior of the casing 1. lThe incoming coal passes through the restricted throat 7 into the first crushing chamber 9. The rapid rotation of the fan-like beaters 30 draws in air through the openings 8, the quantity of air admitted being accurately regulated to effect complete combustion by adjusting the gate 8 to uncover the openings 8 more or lessas desired. The coal upon entering the 4first crushing chamber 9 lismviolently impacted by the` rotating bladesv and driijen against the serrated walls of the chamber, eventually lfind'ing its way th'rough the constricted throat 1l of the chamber into the next chamber where the operation is repeated and so on, until the coal and commingled airescapes from the' final crushing chamber 9 into the discharge chamber 15, and thence by way of the eduction pipe 16 to the combustion chamber. It will be particularlynoted that the action of the rotary membersl-in the crushing chambers not only servesto break up the coal, both by direct impact and propulsion against the ribs or serrations on the wall of the casing, as well asa positive grinding action between the blade vand the serrated walls, but also serves to draw in the air and force the same with a violent swirling or vertical movement through successive chambers by way ofthe constricted throats on openings connecting the said chambers. chamber the combined air and fuel is a lowed to expand `until it is forced forward again through the restricted orifice by the fan blade in that chamber. The combined fuel and air is thereforesubjected to a suc-v cessive expansion and contraction which induces an intimate admixture of the fuel and air durin the successive stages of comminution oft e fuel so that the admixturewf Vcomminuted fuel and air is delivered into the combustion `chamber, where it is ignited and consumed whileina state of suspension and therefore under the best conditions of efficiency and economy. `The provision of the inclined bottoms with the constricted thrcats'in the respective crushing chambers 9 serves the important function of causing the coal and air to move toward the longitudinal axis of the casing as it leaves each chamberl and then tio be thrown out by the ofi' or gate 6 is actuated to open and close 'blades toward the peripheral walls of each chamber so that a thorough and intimate admixture is obtained While the comminution of the fuel is being effected.

By making crushing chambers and propeller elelnents separable and Separate units, it is obvious that should any of the units be broken or damaged, they may be quickly removed and replaced by others, so that should one or more of the elements need replacing this result may be effected Without putting the apparatus out of commission for a considerable length of time.

The apparatus as described is substantially automatic and carries out its function of supplying quantities ofk intimately admixed fuel and air tothe combustion chambers, as long as the fuel is fed to the device and without the attendant danger of explosion which is characteristic of devices of this general type, in which the fuel is comminuted before it is fed to the apparatus and the latter is employed merely for mixing and feeding the fuel and air. When it is desired to suspend the feeding of fuel to the combustion apparatus, it is only necessary to cut ottl the fuel supply and run the apparatus until all of the fuel contained therein is expelled, whereby explosion of residual fuel and air is rendered impossible.

What I claim as my invention is :-l

1. An apparatus for preparing and feeding fine fuel, comprising a casing having a longitudinal series of crushing chambers, connected by restricted orices, a revoluble shaft in said casing, combined air propelling and fuel crushing blades on said shaft and operating in the respective crushing chambers, and inlet and outlet orifices for fuel and air in said casing.

2. An apparatus for preparing and feeding fine fuel, comprising a easing having serrated Walls and a series of transverse dividing plates with eonstricted orifices, forming successive crushing and mixing chambers, revoluble air propelling and fuel crushthe requisite and regulable ing blades operating in the respective chambers, means for supplying fuel and air to said casing and an outlet for delivering mixed air and fuel from the casing.

3. An apparat-us for preparing and feeding fine fuel, comprising a casing provided with a longitudinal series of separate crushing chambers, each having serrated inner Walls, a. constricted orifice, a shaft passing through said chambers, combined air propelling and fuel crushing blades on said Shaft and occupying the respective chambers, means foil supplying regulable quantities of fuel and 'air to said casing, and an outlet for delivering mixed air and fuel from the casing.

` 4. An apparatus for preparing and feeding fine fuel, comprising a casing having inlet and outlet orifices for fuel and air and a series of separable crushing chambers in longitudinal alinement, each having a serrated inner surface and a constricted outlet, a revoluble shaft journaled in the casing, combined air propelling and fuel crushing blades on theshaft and occupying the respective chambers, and a cut olf for the fuel inlet operated from the shaft..

5. An apparatus for prephring and feeding tine fuel, comprising a casing provided with intermediate separable crushing chambers-,"each havmg serrated inner walls and a constricted central outlet, a feed chamber having regulable fuel and air inlets, a discharge chamber with an outlet for mixed fuel and air, a revoluble shaft journaled in the casing, combined air propelling and fuel Crushing blades on Said shaft and operating in the respective crushing chambers, a cut off in the feed chamber, and means for operating said cut off from the shaft.

In testimony whereof I aflix my in presence of two witnesses.

ROBERT PITCAIRN.

signature Witnesses:

A. B. KENNEDY, D. J. NEVILL.

and a transverse dividing plate with 

